Changed type of `number' to size_t.

@@ -66,7 +66,7 @@ typedef struct {
   sieve_data_type type;
   union {
     char *string;
-    long number;
+    size_t number;
     list_t list;
     sieve_runtime_tag_t *tag;
     void *ptr;

@@ -33,7 +33,7 @@ static void branch_fixup __P((size_t start, size_t end));
 
 %union {
   char *string;
-  long number;
+  size_t number;
   sieve_instr_t instr;
   sieve_value_t *value;
   list_t list;